For eight miles, everything was perfect. For the next 18.2 miles, nothing went right.

I came through the first mile marker of the 2011 Chicago Marathon at about 8:05 and comfortably held a steady pace for the next seven, soaking in the energy from the incredible crowd, taking in the view of the city and thoroughly enjoying the start of my first marathon. It was a pristine morning, with the race’s 45,000 participants treated to 64-degree temperatures and a gorgeous blue sky, and my goal of savoring the moment early on instead of obsessing about my time had thus far unfolded as planned.

I crossed the eight-mile marker in just about 64 minutes and prepared to settle in for the next 12 miles, hoping to start shaving some time off my pace before hitting the final six-mile stretch. I knew I’d need to have something left in the tank to finish strong, having topped out four weeks earlier with a 21.5-mile training run, so I was planning on listening to my body to see just how much I could safely push the pace.

I didn’t like what my body had to say.

The good news? My shoulder felt fine. Actually, it felt great. I had a case of subscapular bursitis crop up the previous weekend(NOTE: the injury has since been diagnosed as nerve compression), and while it was a painful injury, I learned during a six-mile run on Thursday and a slow two miler Saturday morning that it actually felt better while running. Hoping to prevent any late-race soreness, I slapped Icy Hot medicated strips onto three different spots of my back, just to be safe. That may very well have been my first mistake of the day.

The bad news? My legs weren’t feeling nearly as good as my shoulder. At a time when I should have been finding a mid-race groove, my legs were tired. Too tired. Certainly too tired for mile 8 of a 26.2-mile race. I knew I would be pushing my body to an extreme that day, but I wasn’t ready to do it yet. Okay, I thought, I’ll just maintain pace for now and hope my legs recover in time for a strong finish. They didn’t.